Field
The disclosure relates to a light source apparatus and a projector having the light source apparatus.
Description of the Related Art
Recently, a time divisional type projector has become popular. The time divisional type projector emits lights of a plurality of wavelengths and forms images by modulating the emitted lights of the plurality of wavelengths sequentially, and then projects the formed images. As a light source apparatus used for the time divisional type projector, for example, there is known a light source apparatus having a light source that outputs a white light, and a rotating wheel to which a plurality of color filters are attached. According to such light source apparatus, the light source emits the white light to the rotating wheel which rotates at constant speed, and thereby emitting lights of a plurality of wavelengths (such as blue, green and red lights) in a time divisional manner.
Further, there is also proposed a light source apparatus including a light source that outputs a light of a single wavelength, such as a laser diode, and a rotating wheel having phosphor layers instead of color filters. According to such light source apparatus, the light source emits the light of a single wavelength to the rotating wheel which rotates at constant speed, and thereby emitting lights of a plurality of wavelengths in a time divisional manner. For example, it is possible to convert wavelength of a blue light from a laser diode into that of a green or red light by using phosphors.
In such light source apparatus, as described in JP 2013-73081 or JP 2012-215633, there is proposed a method to change a location of the light condensed position of each laser diode on the phosphor by varying a distance between the plurality of laser diodes and a distance between collimating lenses located at the output side of the laser light sources, and thereby exciting the phosphors with a low light density.
According to the light source apparatus described in JP 2013-73081 A, JP2012-215633, since the location of the light condensed position of each laser light source is different, the location of the light condensed position can be changed. However, since a diameter of the condensed shape of the parallel light emitted from the collimating lens is small, the light intensity at the light condensed position is so high that the emission efficiency of phosphor is reduced. Further, since a beam shape at the light condensed position of the condenser lens is determined according to a far field pattern or a near field pattern of the laser diode, it is difficult to obtain a beam shape with a desired size or a desired aspect ratio.